Fixed time robust control for tower cranes with unmatched disturbances and input saturation

Abstract

To address the challenging problem of fixed-time anti-sway and positioning control for tower cranes with uncertain disturbances and input saturation, a novel fixed-time anti-saturation robust algorithm is proposed. First, on the basis of a newly designed fixed-time convergence system, a fixed-time disturbance observer (FTDO) is developed to estimate the matched and unmatched disturbances. Then, an anti-saturation compensator is employed to deal with the input saturation and make the control input leave the saturated region rapidly. Upon which, a novel non-singular fast terminal sliding mode surface is presented. Furthermore, in order to ensure the stability of each subsystem, a hierarchical sliding mode surface taking into account unmatched disturbances and input saturation is designed. Finally, the FTDO based hierarchical sliding mode control law is introduced to improve the transient control performance and robustness of tower cranes. The fixed-time convergence of the closed-loop system is proved by Lyapunov technique. Numerical simulations for four scenarios demonstrate the validity of the presented control scheme and fastest convergence speed in comparison to the recently proposed fixed-time control methods.

Model‐reference adaptive and self‐tuning controls of telescopic mobile cranes with the impact of elastic cables, viscoelastic cylinders, and winds

“…The control of cranes has attracted many researchers, with recent articles [5][6][7][8][9][10][11][12][13] on various crane types, from overhead cranes 5,6 and tower cranes [7][8][9] to ship-mounted boom cranes. 10 A crane is a complex nonlinear system with hundreds of machine elements connected to each other.…”

“…Advanced versions of SMC can overcome this problem. Hierarchical SMC 7,8 reduces the chattering at responses but lengthens the reaching phase because it consumes multi-levels of sliding surface. Theoretically, SMC promotes infinite-time stability.…”

“…Theoretically, SMC promotes infinite-time stability. An improvement of SMC, 8 which is nonsingular fast terminal SMC, induces quick convergence with finite time while preventing non-singularity. 7,8 Chattering-free SMC is another version of SMC that utilizes moving sliding surface to eliminate chattering.…”

“…An improvement of SMC, 8 which is nonsingular fast terminal SMC, induces quick convergence with finite time while preventing non-singularity. 7,8 Chattering-free SMC is another version of SMC that utilizes moving sliding surface to eliminate chattering. [14][15][16] Its control structure has integral of the switched function.…”

Hybrid input shaping and fuzzy logic‐based position and oscillation control of tower crane system

“…As described in (Rauscher & Sawodny, 2020), implementation of control strategies on tower cranes is rare due to its complexity and lack of reliable structural dynamics. Some of the few studies that presented the dynamic modelling and control of the TCS are presented in (Gu et al, 2023;Rauscher & Sawodny, 2020;Shan et al, 2022). However, model-based controllers are challenging to design and implement and prone to errors due to uncertainties and assumptions during mathematical modelling.…”